[A long-term evaluation of periodontal phenotypes before and after the periodontal-orthodontic-orthognathic combined treatment of lower anterior teeth in patients with skeletal Angle class Ⅲ malocclusion].

OBJECTIVE

To evaluate the changes of periodontal phenotype (width of keratinized gingiva, thickness and height of alveolar bone) of lower anterior teeth in patients with skeletal class Ⅲ malocclusion before and after the periodontal-orthodontic-orthognathic combined treatment.

METHODS

In the study, 20 patients with skeletal class Ⅲ malocclusion (6 males and 14 females) completed the periodontal-orthodontic-orthognathic combined treatment were included from March 2017 to June 2022, with 39 central incisors, 40 lateral incisors and 40 canines. The mean age was (25.40±4.27) years (20-34 years). The mean follow-up time was (3.70±1.05) years from the beginning of periodontal corticotomy regenerative surgery (PCRS) to the end of the combined treatment. Cone-beam computed tomography (CBCT) was used to measure the thickness, area and height of alveolar bone by the same researcher, taken before the PCRS (T0), 6 months after the PCRS (T1), 12 months after the PCRS (T2), before the orthognathic surgery (T3), and after the periodontal-orthodontic-orthognathic combined treatment (T4). The periodontal clinical parameters were used to evaluate changes in the soft tissue by another researcher, measured before the PCRS (T0) and after the combined treatment (T4). Changes of soft and hard tissue were evaluated by the periodontal phenotype.

RESULTS

The width of keratinized gingiva increased significantly (all < 0.001) in lower anterior teeth, the central incisors, lateral incisors and canines increased by (1.82±1.57) mm, (2.03±1.48) mm and (2.05±1.27) mm, respectively. The proportion of thick periodontal biotype in the central and lateral incisors increased significantly (all < 0.001), while the changes of periodontal biotypes in the lower canines were not obvious. The thickness of labial alveolar bone of lower anterior teeth all increased significantly after periodontal corticotomy regenerative surgery and the combined treatment (all < 0.001). The area of labial alveolar bone of lower anterior teeth also increased significantly after the combined treatment (all < 0.001). The whole area of labial and lingual alveolar bone of central and lateral incisors increased ( < 0.001), while the whole area of canines remained the same. All The height of the alveolar bone increased (all < 0.001) on the labial side after the treatment.

CONCLUSION

The periodontal phenotypes of lower anterior teeth were significantly improved after the periodontal-orthodontic-orthognathic combined treatment in patients with skeletal Angle class Ⅲ malocclusion. The improvement was long-termly stable, and the periodontal risk was reduced.